On Fri, Oct 23, 2009 at 11:47 AM, Jean Delvare <khali@xxxxxxxxxxxx> wrote: > On Thu, 22 Oct 2009 21:13:30 +0200, Jean Delvare wrote: >> For example, the signal strength. All I know so far is that this is a >> 16-bit value. But then what? Do greater values represent stronger >> signal or weaker signal? Are 0x0000 and 0xffff special values? Is the >> returned value meaningful even when FE_HAS_SIGNAL is 0? When >> FE_HAS_LOCK is 0? Is the scale linear, or do some values have >> well-defined meanings, or is it arbitrary and each driver can have its >> own scale? What are the typical use cases by user-space application for >> this value? > > To close the chapter on signal strength... I understand now that we > don't have strict rules about the exact values. But do we have at least > a common agreement that greater values mean stronger signal? I am > asking because the DVB-T adapter model I have here behaves very > strangely in this respect. I get values of: > * 0xffff when there's no signal at all > * 0x2828 to 0x2e2e when signal is OK > * greater values as signal weakens (I have an amplified antenna with > manual gain control) up to 0x7272 > > I would have expected it the other way around: 0x0000 for no signal and > greater values as signal strengthens. I think the frontend driver > (cx22702) needs to be fixed. > > -- > Jean Delvare > -- > To unsubscribe from this list: send the line "unsubscribe linux-media" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > I have a solution for this across the entire DVB subsystem, but I haven't had time to write up a formal explanation. I will follow up with better info when I have time. Regards, Mike Krufky -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
